A curious feature of this picture, at least to my eyes, is that there are no masters. Every other house pic I have seen has the two housemasters and the matron sitting in the centre. Perhaps, it was a Prep thing?

Middle row, third from right is a boy named Heath.
Second row down, the boy with the disgracefully crooked bands is John Rees, known as "Tick".
Second row down, 3rd from left: the late Nick Johnstone
middle row, 8th from left: Keith Hildrew
top row, fourth from right: Tim Huntingford